A prospective study of healthful and unhealthful plant-based diet and risk of overall and cause-specific mortality.

Abstract

Although emphasis has recently been placed on the importance of diet high in plant-based foods, the association between plant-based diet and long-term risk of overall and cause-specific mortality has been less studied. We aimed to investigate whether plant-based diet was associated with lower death risk. This prospective cohort study used data from the US National Health and Nutrition Examination Survey. Diet was assessed using 24h dietary recalls. We created three plant-based diet indices including an overall plant-based diet index (PDI), a healthful plant-based diet index (hPDI), and an unhealthful plant-based diet index (uPDI). Deaths from baseline until December 31, 2015, were identified. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox regression. We documented 4904 deaths among 40,074 participants after a median follow-up of 7.8years. Greater adherence to PDI was associated with lower risk of overall (HR comparing extreme quintiles 0.80, 95% CI 0.73, 0.89, ptrend < 0.001) and cancer-specific (HR = 0.68, 95% CI 0.55, 0.85, ptrend < 0.001) mortality. These inverse associations remained for hPDI and overall mortality with a HR of 0.86 (95% CI 0.77, 0.95, ptrend = 0.001), but not for cancer or CVD mortality. Conversely, uPDI was associated with higher risk of total (HR = 1.33, 95% CI 1.19, 1.48, ptrend < 0.001) and CVD-specific (HR = 1.42, 95% CI 1.12, 1.79, ptrend = 0.015) mortality. Increased intake of a plant-based diet rich in healthier plant foods is associated with lower mortality risk, whereas a plant-based diet that emphasizes less-healthy plant foods is associated with high mortality risk among US adults.